Prognostic Value of Undetectable hs Troponin T in Suspected Acute Coronary Syndrome

The new ESC acute coronary syndrome guideline and its impact in the CPU and emergency department setting

The new guideline on acute coronary syndrome (ACS) of the European Society of Cardiology (ESC) replaces two separate guidelines on ST-elevation myocardial infarction (STEMI) and non-ST-elevation (NSTE) ACS. This change of paradigm reflects the experts view that the ACS is a continuum, starting with unstable angina and ending in cardiogenic shock or cardiac arrest due to severe myocardial ischemia. Secondary, partly non-atherosclerotic-caused myocardial infarctions ("type 2") are not integrated in this concept.With respect to acute care in the setting of emergency medicine and the chest pain unit structures, the following new aspects have to be taken into account:1. New procedural approach as "think A.C.S." meaning "abnormal ECG," "clinical context," and "stable patient"2. New recommendation regarding a holistic approach for frail patients3. Revised recommendations regarding imaging and timing of invasive strategy in suspected NSTE-ACS4. Revised recommendations for antiplatelet and anticoagulant therapy in STEMI5. Revised recommendations for cardiac arrest and out-of-hospital cardiac arrest6. Revised recommendations for in-hospital management (starting in the CPU/ED) and ACS comorbid conditionsIn summary, the changes are mostly gradual and are not based on extensive new evidence, but more on focused and healthcare process-related considerations.

Derivation and external validation of machine-learning models for risk stratification in chest pain with normal troponin

AIMS

Risk stratification of patients with chest pain and a high-sensitivity cardiac troponin T (hs-cTnT) concentration

METHODS AND RESULTS

Four machine-learning-based models and one logistic regression (LR) model were trained on 4075 patients (single-centre Spanish cohort) and externally validated on 3609 patients (international prospective Advantageous Predictors of Acute Coronary syndromes Evaluation cohort). Models were compared with GRACE and HEART scores and a single undetectable hs-cTnT-based strategy (u-cTn; hs-cTnT < 5 ng/L and time from symptoms onset >180 min). Probability thresholds for safe discharge were derived in the derivation cohort. The endpoint occurred in 105 (2.6%) patients in the training set and 98 (2.7%) in the external validation set. Gradient boosting full (GBf) showed the best discrimination (area under the curve = 0.808). Calibration was good for the reduced neural network and LR models. Gradient boosting full identified the highest proportion of patients for safe discharge (36.7 vs. 23.4 vs. 27.2%; GBf vs. LR vs. u-cTn, respectively) with similar safety (missed endpoint per 1000 patients: 2.2 vs. 3.5 vs. 3.1, respectively). All derived models were superior to the HEART and GRACE scores (P < 0.001).

CONCLUSION

Machine-learning and LR prediction models were superior to the HEART, GRACE, and u-cTn for risk stratification of patients with chest pain and a baseline hs-cTnT

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov number, NCT00470587, https://clinicaltrials.gov/ct2/show/NCT00470587.

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Key Words

• Machine learning
• Myocardial infarction
• Prediction
• Troponin

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MESH Headings

• Humans
• Troponin
• Prospective Studies
• Biomarkers
• Troponin T
• Chest Pain/diagnosis
• Chest Pain/etiology
• Risk Assessment

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Grants

• Swiss National Science Foundation

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Affiliation(s)

Agustín Fernández-Cisnal Cardiology Department, Hospital Clínico Universitario de València, Instituto de Investigación Sanitaria (INCLIVA), University of València, Centro de Investigación Biomédica en Red Enfermedades Cardiovaculares (CIBERCV), València, Spain
Pedro Lopez-Ayala Cardiovascular Research Institute Basel (CRIB) and Department of Cardiology, University Heart Center Basel, University Hospital Basel, University of Basel, Basel, Switzerland
Ernesto Valero Cardiology Department, Hospital Clínico Universitario de València, Instituto de Investigación Sanitaria (INCLIVA), University of València, Centro de Investigación Biomédica en Red Enfermedades Cardiovaculares (CIBERCV), València, Spain
Luca Koechlin Cardiovascular Research Institute Basel (CRIB) and Department of Cardiology, University Heart Center Basel, University Hospital Basel, University of Basel, Basel, Switzerland
Arturo Catarralá Clinical Biochemistry Department, Hospital Clínico Universitario de València, Instituto de Investigación Sanitaria (INCLIVA), València 46010, Spain
Jasper Boeddinghaus Cardiovascular Research Institute Basel (CRIB) and Department of Cardiology, University Heart Center Basel, University Hospital Basel, University of Basel, Basel, Switzerland
José Noceda Emergency Department, Hospital Clínico Universitario de València, Instituto de Investigación Sanitaria (INCLIVA), València 46010, Spain
Thomas Nestelberger Cardiovascular Research Institute Basel (CRIB) and Department of Cardiology, University Heart Center Basel, University Hospital Basel, University of Basel, Basel, Switzerland
Òscar Miró Emergency Department, Hospital Clinic, Barcelona, Catalonia, Spain
Núñez Julio Cardiology Department, Hospital Clínico Universitario de València, Instituto de Investigación Sanitaria (INCLIVA), University of València, Centro de Investigación Biomédica en Red Enfermedades Cardiovaculares (CIBERCV), València, Spain
Christian Mueller Cardiovascular Research Institute Basel (CRIB) and Department of Cardiology, University Heart Center Basel, University Hospital Basel, University of Basel, Basel, Switzerland
Juan Sanchis Cardiology Department, Hospital Clínico Universitario de València, Instituto de Investigación Sanitaria (INCLIVA), University of València, Centro de Investigación Biomédica en Red Enfermedades Cardiovaculares (CIBERCV), València, Spain

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Major adverse cardiac events after emergency department evaluation of chest pain patients with advanced testing: Systematic review and meta-analysis

OBJECTIVES

Our primary objective was to describe the risk of major adverse cardiac events (MACE) at 1, 6, and 12 months after a negative coronary computed tomography angiogram (cCTA), electrocardiogram (ECG) stress test, stress echocardiography, and myocardial perfusion scintigraphy (MPS) in low- to intermediate-risk patients.

METHODS

Initially, 952 articles were identified for screening, 81 met criteria for full-text review, and once risk of bias was assessed, 33 articles were included in this meta-analysis. We utilized a random-effects model to assess pooled MACE event proportion for patients undergoing evaluation of acute coronary syndrome (ACS) when risk stratified to a low- to intermediate-risk category after undergoing standard testing. Heterogeneity analysis was performed using Cochrane's Q-test and I² statistic.

RESULTS

Twenty-one studies evaluated follow-up at 1 month with cCTA having a 0.09% (95% confidence interval [CI] = 0.03% to 0.26%) pooled MACE compared to 0.23% (95% CI = 0.01% to 5.8%) of the exercise stress testing (p = 1). MPS and cCTA had an overall event rate of 0.15% (95% CI = 0.06% to 0.41%) at 6 months (I²  = 0%). At 12 months, a subgroup analysis found a pooled cCTA MACE of 0.16% (95% CI = 0.04% to 0.65%) compared to 1.68% (95% CI = 0.01% to 2.6%) for stress echocardiography with low within-group heterogeneity (I²  = 0%). Subgroup analysis of cCTA with no disease versus nonobstructive disease (<50% stenosis) did not find statistical difference in the MACE at both 1 month (0.17% [95% CI = 0.04% to 0.67%] vs. 0.06% [95% CI = 0.01% to 0.34%]) and 12 months (0.44% [95% CI = 0.09% to 2.2% vs. 0.54% [95% CI = 0.19% to 1.5%]).

CONCLUSIONS

Patients presenting with chest pain who have a coronary CTA showing < 50% stenosis, negative ECG stress test, stress echocardiography, or stress myocardial perfusion scan in the past 12 months can be discharged without any further risk stratification if their ECG and troponin are reassuring given low MACE.

Potential impact of a novel pathway for suspected myocardial infarction utilising a new high-sensitivity cardiac troponin I assay

BACKGROUND

High-sensitivity cardiac troponin I (hs-cTnI) assays promise high diagnostic accuracy for myocardial infarction (MI). In an ED where conventional cTnI was in use, we evaluated an assessment pathway using the new Access hsTnI assay.

METHODS

This retrospective analysis recruited ED patients with suspected MI between June and September 2019. All patients received routine care with a conventional cTnI assay (AccuTnI +3: limit of detection (LoD) 10 ng/L, 99th centile upper reference limit (URL) 40 ng/L, abnormal elevation cut-point 80 ng/L). Arrival, then 90-minute or 360-minute cTnI levels for low and non-low risk patients, respectively (ED Assessment of Chest pain score) guided diagnosis and disposition which was at treating physician discretion. The same patients had arrival and 90-minute or 180-minute samples drawn for hs-cTnI levels (Access hsTnI: LoD 2 ng/L, 99th centile URL 10 ng/L (females) and 20 ng/L (males); abnormal elevation above the URL and delta >30%). Treating physicians were blinded to the hs-cTnI results. Using the hs-cTnI values, investigators retrospectively assigned likely diagnosis, disposition and likelihood of a 30-day major adverse cardiac event (MACE). Admission was recommended for significantly rising hs-cTnI elevations. The primary objective was to demonstrate an acceptable unexpected 30-day post-discharge MACE rate of <1%. cTnI elevation rates, diagnostic outcomes and ED disposition were also compared between pathways.

RESULTS

For the 935 patients, unexpected 30-day post-discharge MACE rates were 0/935 (0%, 95% CI 0% to 0.4%) with the conventional or novel pathway. For the high-sensitivity and conventional assays, respectively, abnormal elevation rates were 29% (95% CI 26% to 32%) and 19% (95% CI 17% to 22%), for MI were 9% (95% CI 8% to 11%) and 8% (95% CI 6% to 10%), and for hospital admission were 42% (95% CI 39% to 45%) and 43% (95% CI 40% to 47%).

CONCLUSION

The novel pathway using the Access hsTnI assay has an acceptably low 30-day MACE rate.

Critical appraisal of the 2020 ESC guideline recommendations on diagnosis and risk assessment in patients with suspected non-ST-segment elevation acute coronary syndrome

Multiple new recommendations have been introduced in the 2020 ESC guidelines for the management of acute coronary syndromes with a focus on diagnosis, prognosis, and management of patients presenting without persistent ST-segment elevation. Most recommendations are supported by high-quality scientific evidence. The guidelines provide solutions to overcome obstacles presumed to complicate a convenient interpretation of troponin results such as age-, or sex-specific cutoffs, and to give practical advice to overcome delays of laboratory reporting. However, in some areas, scientific support is less well documented or even missing, and other areas are covered rather by expert opinion or subjective recommendations. We aim to provide a critical appraisal on several recommendations, mainly related to the diagnostic and prognostic assessment, highlighting the discrepancies between Guideline recommendations and the existing scientific evidence.

Divergence of Cardiovascular Biomarkers of Lipids and Subclinical Myocardial Injury Among Rheumatoid Arthritis Patients With Increased Inflammation

OBJECTIVE

Patients with rheumatoid arthritis (RA) are 1.5 times more likely to develop cardiovascular disease (CVD) attributed to chronic inflammation. A decrease in inflammation in patients with RA is associated with increased low-density lipoprotein (LDL) cholesterol. This study was undertaken to prospectively evaluate the changes in lipid levels among RA patients experiencing changes in inflammation and determine the association with concomitant temporal patterns in markers of myocardial injury.

METHODS

A total of 196 patients were evaluated in a longitudinal RA cohort, with blood samples and high-sensitivity C-reactive protein (hsCRP) levels measured annually. Patients were stratified based on whether they experienced either a significant increase in inflammation (an increase in hsCRP of ≥10 mg/liter between any 2 time points 1 year apart; designated the increased inflammation cohort [n = 103]) or decrease in inflammation (a decrease in hsCRP of ≥10 mg/liter between any 2 time points 1 year apart; designated the decreased inflammation cohort [n = 93]). Routine and advanced lipids, markers of inflammation (interleukin-6, hsCRP, soluble tumor necrosis factor receptor II), and markers of subclinical myocardial injury (high-sensitivity cardiac troponin T [hs-cTnT], N-terminal pro-brain natriuretic peptide) were measured.

RESULTS

Among the patients in the increased inflammation cohort, the mean age was 59 years, 81% were women, and the mean RA disease duration was 17.9 years. The average increase in hsCRP levels was 36 mg/liter, and this increase was associated with significant reductions in LDL cholesterol, triglycerides, total cholesterol, apolipoprotein (Apo B), and Apo A-I levels. In the increased inflammation cohort at baseline, 45.6% of patients (47 of 103) had detectable circulating hs-cTnT, which further increased during inflammation (P = 0.02). In the decreased inflammation cohort, hs-cTnT levels remained stable despite a reduction in inflammation over follow-up. In both cohorts, hs-cTnT levels were associated with the overall estimated risk of CVD.

CONCLUSION

Among RA patients who experienced an increase in inflammation, a significant decrease in routinely measured lipids, including LDL cholesterol, and an increase in markers of subclinical myocardial injury were observed. These findings highlight the divergence in biomarkers of CVD risk and suggest a role in future studies examining the benefit of including hs-cTnT for CVD risk stratification in RA.

Prognostic value of copeptin in patients with acute coronary syndrome: A systematic review and meta-analysis

Background

The aim of this study was to evaluate the value of copeptin in predicting mortality including both short-term and long-term mortality in patients with acute coronary syndrome (ACS).

Methods

Potential studies were searched and selected through PubMed, Embase and Cochrane databases up to December 2019. The predictive performance was evaluated by the pooled sensitivity and specificity, and summary receiver operating characteristic curves. Cochran’s Q test and I² index were used to assess between-study heterogeneity, and Deek’s test and funnel plots were used to assess publication bias.

Results

Total six studies comprising 2269 patients were included in this meta-analysis. The area under the receiver operating characteristic curve of copeptin in predicting mortality in patients with ACS was 0.73 (95% CI: 0.69–0.77). The pooled sensitivity and specificity of copeptin were 0.77 (95% CI: 0.59–0.89) and 0.60 (95% CI: 0.47–0.71), respectively. Significant between-study heterogeneity was identified in both sensitivity (P = 0.01; I² = 69.76%) and specificity (P<0.001; I² = 97.32%) among the six included studies. The meta-regression analysis indicated that the number of study centers was significantly associated with the heterogeneity of sensitivity (P = 0.03), whereas the study design (P = 0.03) and duration of follow-up (P<0.001) were significantly associated with the heterogeneity of specificity.

Conclusions

Copeptin has acceptable prognostic value for mortality in patients with ACS. Further studies based on multimarker strategy are needed to evaluate the prognostic value of copeptin for ACS in conjunction with other well-established biomarkers.

Undetectable high-sensitivity troponin in combination with clinical assessment for risk stratification of patients with chest pain and normal troponin at hospital arrival

BACKGROUND

Undetectable high-sensitivity cardiac troponin (hs-cTn) in a single determination upon admission may rule out acute coronary syndrome. We investigated undetectable hs-cTnT (<detection limit; <5 ng/l) together with clinical risk scores (GRACE, TIMI, HEART and a previously published simple score), for one-year outcomes in patients with chest pain and normal hs-cTnT (<99th percentile; <14 ng/l) upon admission.

METHODS

This study was a retrospective design involving 2254 consecutive patients (July 2016-November 2017). The primary endpoint was one-year death or acute myocardial infarction; the secondary endpoint added unstable angina requiring revascularization. Early (<90 minutes since pain onset, n = 661) and late (n = 1593) presenters were separately considered.

RESULTS

A total of 56 (2.5%) patients reached the primary endpoint and 91 (4%) the secondary endpoint. Undetectable hs-cTnT had a poor C-statistic in early and late presenters (0.648 and 0.703, respectively). Adding hs-cTnT measurable concentrations above the detection limit (as continuous variable) significantly enhanced the C-statistics (0.754 and 0.847, respectively). Addition of the HEART (0.809, p = 0.005) or simple clinical scores (0.804, p = 0.02) further improved the model and significantly reclassified patient risk, in early presenters. The results were similar for the secondary endpoint. The TIMI risk score performed worse and the GRACE score did not give additional information. In late presenters, no clinical score provided significant additional information over hs-cTnT.

CONCLUSIONS

Diagnostic algorithms should consider not only whether hs-cTnT is above or below the detection limit but also its concentration if above, for risk stratification over one year in patients with initial normal hs-cTnT. The clinical scores provide valuable additional information in early presenters.

Low High-Sensitivity Troponin Thresholds Identify Low-Risk Patients With Chest Pain Unlikely to Benefit From Further Risk Stratification

Background

Very low high-sensitivity cardiac troponin T (hs-cTnT) thresholds on presentation can rule out acute myocardial infarction (AMI), but the ability to identify patients at low risk of 30-day major adverse cardiac events (MACE) is less clear. This study examines the sensitivity of low concentrations of hs-cTnT on presentation to rule out 30-day MACE.

Methods

This prospective cohort study enrolled patients with chest pain presenting to the emergency department with nonischemic electrocardiograms who underwent AMI rule-out with an hs-cTnT assay. The primary outcome was 30-day MACE; secondary outcomes were individual MACE components. Because guidelines recommend using a single hs-cTnT strategy only for patients with more than 3 hours since symptom onset, a subgroup analysis was performed for this population. Outcomes were adjudicated on the basis of review of medical records and telephone follow-up.

Results

Of 1167 patients enrolled, 125 (10.7%) experienced 30-day MACE and 97 (8.3%) had AMI on the index visit. More than one-third of patients (35.6%) had presenting hs-cTnT concentrations below the limit of detection (5 ng/L), which was 94.4% (95% confidence interval [CI], 88.8-97.7) sensitive for 30-day MACE and 99.0% (95% CI, 94.5-100) sensitive for index AMI. Of 292 patients (25.0%) with hs-cTnT < 5 ng/L and at least 3 hours since symptom onset, only 3 experienced 30-day MACE (sensitivity 97.6%; 95% CI, 93.2-100) and none had AMI within 30 days (sensitivity 100%; 95% CI, 96.3-100).

Conclusions

Among patients with nonischemic electrocardiograms and > 3 hours since symptom onset, low hs-cTnT thresholds on presentation confer a very low risk of 30-day MACE. In the absence of a high-risk clinical presentation, further risk stratification is likely to be low yield.

Multicentre cross-sectional observational registry to monitor the safety of early discharge after rule-out of acute myocardial infarction by copeptin and troponin: the Pro-Core registry

OBJECTIVES

There is sparse information on the safety of early primary discharge from the emergency department (ED) after rule-out of myocardial infarction in suspected acute coronary syndrome (ACS). This prospective registry aimed to confirm randomised study results in patients at low-to-intermediate risk, with a broader spectrum of symptoms, across different institutional standards and with a range of local troponin assays including high-sensitivity cTn (hs-cTn), cardiac troponin (cTn) and point-of-care troponin (POC Tn).

DESIGN

Prospective, multicentre European registry.

SETTING

18 emergency departments in nine European countries (Germany, Austria, Switzerland, France, Spain, UK, Turkey, Lithuania and Hungary) PARTICIPANTS: The final study cohort consisted of 2294 patients (57.2% males, median age 57 years) with suspected ACS.

INTERVENTIONS

Using the new dual markers strategy, 1477 patients were eligible for direct discharge, which was realised in 974 (42.5%) of patients.

MAIN OUTCOME MEASURES

The primary endpoint was all-cause mortality at 30 days.

RESULTS

Compared with conventional workup after dual marker measurement, the median length of ED stay was 60 min shorter (228 min, 95% CI: 219 to 239 min vs 288 min, 95% CI: 279 to 300 min) in the primary dual marker strategy (DMS) discharge group. All-cause mortality was 0.1% (95% CI: 0% to 0.6%) in the primary DMS discharge group versus 1.1% (95% CI: 0.6% to 1.8%) in the conventional workup group after dual marker measurement. Conventional workup instead of discharge despite negative DMS biomarkers was observed in 503 patients (21.9%) and associated with higher prevalence of ACS (17.1% vs 0.9%, p<0.001), cardiac diagnoses (55.2% vs 23.5%, p<0.001) and risk factors (p<0.01), but with a similar all-cause mortality of 0.2% (95% CI: 0% to 1.1%) versus primary DMS discharge (p=0.64).

CONCLUSIONS

Copeptin on top of cardiac troponin supports safe discharge in patients with chest pain or other symptoms suggestive of ACS under routine conditions with the use of a broad spectrum of local standard POC, conventional and high-sensitivity troponin assays.

TRIAL REGISTRATION NUMBER

NCT02490969.

[Biomarkers in the diagnosis of cardiovascular emergencies : Acute coronary syndrome and differential diagnoses]

In emergency situations, patients present with symptoms rather than diagnoses. Due to its high prevalence, the acute coronary syndrome (ACS) dominates acute diagnostics as a consequence of its chief complaint chest pain. The challenge for the attending physicians is that only a minor part of patients with chest pain are finally diagnosed with an acute myocardial infarction (AMI) and that other rare but dangerous differential diagnoses have to be kept in mind and-vice versa-severely ill patients with AMI may present with symptoms other than chest pain. Against this background, the initial evaluation of patients requires a process-orientated view beyond the key roles of clinical assessment and biomarkers. The use of cardiac troponin is mandatory for the diagnosis of ACS, but challenging in broader utilization due to the reduced clinical specificity. Further relevant biomarkers are copeptin in combination with cardiac troponin or natriuetic peptides, which help to diagnose relevant cardiac dysfunction in (acute) heart failure. In addition, patients who present with the symptom of a suspected cardiac syncope need the differential diagnosis of an underlying arrhythmia, which may be due to an ACS or reduced left ventricular (LV) function and other causes like pulmonary embolism or structural heart disease (e. g. aortic valve stenosis). This highlights that biomarker-based diagnostics are often crucial to decide after the initial clinical evaluation whether early imaging is needed or early discharge is possible.

Role of High-sensitivity Cardiac Troponin in Acute Coronary Syndrome

Chest pain is one of the most common reasons for an emergency room (ER) visit in the US, with almost 6 million ER visits annually. High-sensitivity cardiac troponin (hscTn) assays have the ability to rapidly rule in or rule out acute coronary syndrome with improved sensitivity, and they are increasingly being used. Though hscTn assays have been approved for use in European, Australian, and Canadian guidelines since 2010, the FDA only approved their use in 2017. There is no consensus on how to compare the results from various hscTn assays. A literature review was performed to analyze the advantages and limitations of using hscTn as a standard biomarker to evaluate patients with suspected ACS in the emergency setting.

Pre-test characteristics of unstable angina patients with obstructive coronary artery disease confirmed by coronary angiography

Objective

Patients referred for acute coronary angiography (CAG) with unstable angina (UA) have low mortality and low rate of obstructive coronary artery disease (CAD). Better pre-test selection criteria are warranted. We aimed to assess the current guidelines against other clinical variables as predictors of obstructive CAD in patients with UA referred for acute CAG.

Methods

From 2005 to 2012, all CAGs performed at the University Hospital of North Norway, the sole provider of CAG in the region, were recorded in a registry. We included 979 admissions of UA and retrospectively collected data regarding presenting clinical parameters from patient hospital records. Obstructive CAD was defined as ≥50% stenosis and considered prognostically significant if found in the left main stem, proximal LAD or all three main coronary arteries. Characteristics were analysed by logistic regression analysis. A score was developed using ORs from significant factors in a multivariable model.

Results

The overall rate of obstructive CAD was 45%, and the rate of prognostically significant CAD was 11%. The risk criteria recommended in American College of Cardiology/American Heart Association and European Society of Cardiology guidelines had an area under the curve (AUC) of 0.58. Adding clinical information increased the AUC to 0.77 (95% CI 0.74 to 0.80). Applying the derived score, we found that 56% (n=546) of patients had a score of <13, which was associated with a negative predictive value of 95% for prognostic significant CAD.

Conclusions

The current results suggest that CAG may be postponed or cancelled in more than half of patients with UA by improving pre-test selection criteria with the addition of clinical parameters to current guidelines.

Combined testing of copeptin and high-sensitivity cardiac troponin T at presentation in comparison to other algorithms for rapid rule-out of acute myocardial infarction

BACKGROUND

We aimed to directly compare the diagnostic and prognostic performance of a dual maker strategy (DMS) with combined testing of copeptin and high-sensitivity (hs) cardiac troponin T (cTnT) at time of presentation with other algorithms for rapid rule-out of acute myocardial infarction (AMI).

METHODS

922 patients presenting to the emergency department with suspected AMI and available baseline copeptin measurements qualified for the present TRAPID-AMI substudy. Diagnostic measures using the DMS (copeptin <10, <14 or < 20 pmol/L and hs-cTnT≤14 ng/L), the 1 h-algorithm (hs-cTnT<12 ng/L and change <3 ng/L at 1 h), as well as the hs-cTnT limit-of-blank (LoB, <3 ng/L) and -detection (LoD, <5 ng/L) were compared. Outcomes were assessed as combined end-points of death and myocardial re-infarction.

RESULTS

True-negative rule-out using the DMS could be achieved in 50.9%-62.3% of all patients compared to 35.0%, 45.3% and 64.5% using LoB, LoD or the 1 h-algorithm, respectively. The DMS showed NPVs of 98.1%-98.3% compared to 99.2% for the 1 h-algorithm, 99.4% for the LoB and 99.3% for the LoD. Sensitivities were 93.5%-94.8%, as well as 96.8%, 98.7% and 98.1%, respectively. Addition of clinical low-risk criteria such as a HEART-score ≤ 3 to the DMS resulted in NPVs and sensitivities of 100% with a true-negative rule-out to 33.8%-41.6%. Rates of the combined end-point of death/MI within 30 days ranged between 0.2% and 0.3% for all fast-rule-out protocols.

CONCLUSION

Depending on the applied copeptin cut-off and addition of clinical low-risk criteria, the DMS might be an alternative to the hs-cTn-only-based algorithms for rapid AMI rule-out with comparable diagnostic measures and outcomes.

Prognostic implications of detectable cardiac troponin I below the 99th percentile in patients admitted to an emergency department without acute coronary syndrome

Background:

Detectable troponin below the 99th percentile may reflect an underlying cardiac abnormality which might entail prognostic consequences. This study aimed to investigate the prognosis of patients admitted to an emergency department (ED) with detectable troponin below the 99th percentile reference limit who did not present with an acute coronary syndrome (ACS).

Methods:

We analysed the clinical data of all consecutive patients admitted to the ED during the years 2012 and 2013 in whom cardiac troponin was requested by the attending clinician (cTnI Ultra Siemens, Advia Centaur). Patients with troponin below the 99th percentile of the reference population (40 ng/L) and who did not have a diagnosis of ACS were selected, and their mortality was evaluated in a 2-year follow-up.

Results:

A total of 2501 patients had a troponin level below the reference limit, with 43.9% of those showing detectable levels (>6 ng/L and <40 ng/L). Patients with detectable levels were elderly and had a higher prevalence of cardiovascular history and more comorbidities. The total mortality in the 2-year follow-up was 12.4% in patients with detectable troponin and 4.5% in patients with undetectable troponin (p<0.001). In the Cox multivariate regression analysis, the detectable troponin was an independent marker of mortality at 2 years (HR 1.62, 95% CI 1.07–2.45, p=0.021).

Conclusions:

Detectable troponin I below the 99th percentile is associated with higher mortality risk at 2-year follow-up in patients admitted to the ED who did not present with ACS.

Cysteine-rich angiogenic inducer 61 (Cyr61): a novel soluble biomarker of acute myocardial injury improves risk stratification after acute coronary syndromes

Aims

We aimed to identify a novel biomarker involved in the early events leading to an acute coronary syndrome (ACS) and evaluate its role in diagnosis and risk stratification.

Methods and results

Biomarker identification was based on gene expression profiling. In coronary thrombi of ACS patients, cysteine-rich angiogenic inducer 61 (Cyr61, CCN1) gene transcripts were highly up-regulated compared with peripheral mononuclear cells. In a murine ischaemia-reperfusion model (I/R), myocardial Cyr61 expression was markedly increased compared with the controls. Cyr61 levels were determined in human serum using an enzyme-linked immunosorbent assay. Cohorts of ACS (n = 2168) referred for coronary angiography, stable coronary artery disease (CAD) (n = 53), and hypertrophic obstructive cardiomyopathy (HOCM) patients (n = 15) served to identify and evaluate the diagnostic and prognostic performance of the biomarker. Cyr61 was markedly elevated in ST-elevation myocardial infarction patients compared with non-ST-elevation myocardial infarction/unstable angina or stable CAD patients, irrespective of whether coronary thrombi were present. Cyr61 was rapidly released after occlusion of a septal branch in HOCM patients undergoing transcoronary ablation of septal hypertrophy. Cyr61 improved risk stratification for all-cause mortality when added to the reference GRACE risk score at 30 days (C-statistic 0.88 to 0.89, P = 0.001) and 1 year (C-statistic 0.77 to 0.80, P < 0.001) comparable to high-sensitivity troponin T (30 days: 0.88 to 0.89, P < 0.001; 1 year: 0.77 to 0.79, P < 0.001). Similar results were obtained for the composite endpoint of all-cause mortality or myocardial infarction. Conversely, in a population-based case-control cohort (n = 362), Cyr61 was not associated with adverse outcome.

Conclusion

Cyr61 is a novel early biomarker reflecting myocardial injury that improves risk stratification in ACS patients.

High-sensitivity cardiac troponin T for diagnosis of NSTEMI in the elderly emergency department patient: a clinical cohort study

PURPOSE

The aim of this study is to evaluate the impact of age on the diagnostic performance of high-sensitivity troponin T (hsTnT) under routine conditions.

MATERIALS AND METHODS

Data of 4118 consecutive emergency department (ED) patients who underwent a routine TnT measurement between 11 October 2012 and 30 November 2013 were analysed. Diagnostic accuracy of hsTnT was compared in four age categories (<50, 50-64, 65-74, ≥75 years of age) for different cut-off values. Primary endpoint was a main hospital diagnosis of NSTEMI.

RESULTS

The median age of the study population (n = 4118) was 61 years (IQR: 45-75 years). NSTEMI was diagnosed in 3.3% (n = 136) of all patients. There were significant differences in hsTnT concentrations between age-groups (p < 0.001) in all patients, but not in NSTEMI patients (p = 0.297). 72.2% of all patients ≥75 years of age (583/808) without NSTEMI had hsTnT concentrations above the 99th percentile of a healthy reference population. Specificity at 14 ng/L was 93.6% (95% CI: 92.12-94.87) in patients below 50 years of age and 27.9% (95% CI: 24.78-31.08) in patients 75 years of age and older.

CONCLUSIONS

Patients' age needs to be considered at least one influencing factor on hsTnT concentrations at admission and should be included in the clinical interpretation of hsTnT concentrations for further clinical workup beneath other influencing factors like comorbidities and symptom onset time. The implementation of age-specific cut-off values could be considered for single troponin testing at admission but is associated with an increased risk of underdiagnosis of NSTEMI.

Contemporary Emergency Department Management of Patients with Chest Pain: A Concise Review and Guide for the High-Sensitivity Troponin Era

This article synthesizes current best evidence for the evaluation of patients with suspected acute coronary syndrome (ACS) using high-sensitivity troponin assays, enabling physicians to effectively incorporate them into practice. Unlike conventional assays, high-sensitivity assays can precisely measure blood cardiac troponin concentrations in the vast majority of healthy individuals, facilitating the creation of rapid diagnostic algorithms. Very low troponin concentrations on presentation accurately rule out acute myocardial infarction (AMI) and enable the discharge of approximately 20% of patients after a single test, whereas an additional 30%-40% of patients can be safely discharged after short-interval serial sampling in as little as 1 or 2 hours. In contrast, highly abnormal troponin concentrations on presentation (more than 5 times the upper reference limit) or rapidly rising levels on serial testing can rapidly rule in AMI with high specificity. However, approximately one-third of patients remain in a biomarker-indeterminate "observation zone" even after serial sampling. These patients pose a disposition challenge to clinicians because although the differential diagnosis of elevated troponin concentrations is broad, these patients have an increased risk for short-term major adverse cardiac events. Use of repeated serial troponin sampling and structured clinical prediction tools may assist disposition for these patients, because no validated pathways currently exist to guide clinicians. Ongoing research to tailor diagnostic thresholds to individual patient characteristics may enable improved diagnostic accuracy and usher in a new era of personalized medicine in the evaluation of suspected ACS.

The copeptin response after physical activity is not associated with cardiac biomarkers or asymptomatic coronary artery disease: The North Sea Race Endurance Exercise Study (NEEDED) 2013

BACKGROUND

Copeptin concentrations increase both during acute coronary syndrome and following physical exercise. The relationship between copeptin increase following physical exercise and coronary artery disease (CAD) is uncertain. The aim of this study was to 1) describe the copeptin response following strenuous physical exercise, and 2) investigate the determinants of exercise induced copeptin concentrations, particularly in relation to cardiac biomarkers and CAD.

METHODS

Serum samples were collected from 97 recreational cyclists 24h before, and immediately, 3 and 24h after a 91-km bike race. Three subjects were subsequently diagnosed with significant asymptomatic CAD. Delta copeptin concentrations were correlated to patient characteristics and to biomarker concentrations.

RESULTS

Participants were 42.8±9.6years, and 76.3% were male. Copeptin concentrations increased to maximal levels immediately after the race and were normalized in >90% after 3h. A total of 53% and 39% exceeded the 95th and 99th percentile of the assay (10 and 19pmol/L) respectively. In multivariate models, race time, serum sodium, creatinine and cortisol were significant predictors of copeptin levels. There was no correlation between changes in copeptin and changes in cardiac biomarkers (hs-cTnI, hs-cTnT and BNP). Copeptin concentrations were normal in the subjects with asymptomatic CAD.

CONCLUSIONS

The moderate, short-term, exercise induced copeptin increase observed in the present study was not related to hs-cTn or BNP levels. Copeptin was normal in three asymptomatic recreational athletes with significant CAD.

Single High-Sensitivity Cardiac Troponin I to Rule Out Acute Myocardial Infarction

BACKGROUND

This study examined the performance of single high-sensitivity cardiac troponin I (hs-cTnI) measurement strategies to rule out acute myocardial infarction.

METHODS

This was a prospective, observational study of consecutive patients presenting to the emergency department (n = 1631) in whom cTnI measurements were obtained using an investigational hs-cTnI assay. The goals of the study were to determine 1) negative predictive value (NPV) and sensitivity for the diagnosis of acute myocardial infarction, type 1 myocardial infarction, and type 2 myocardial infarction; and 2) safety outcome of acute myocardial infarction or cardiac death at 30 days using hs-cTnI less than the limit of detection (LoD) (<1.9 ng/L) or the High-STEACS threshold (<5 ng/L) alone and in combination with normal electrocardiogram (ECG).

RESULTS

Acute myocardial infarction occurred in 170 patients (10.4%), including 68 (4.2%) type 1 myocardial infarction and 102 (6.3%) type 2 myocardial infarction. For hs-cTnI<LoD (27%), the NPV and sensitivity for acute myocardial infarction were 99.6% (95% confidence interval 98.9%-100%) and 98.8 (97.2%-100%). For hs-cTnI<5 ng/L (50%), the NPV and sensitivity for acute myocardial infarction were 98.9% (98.2%-99.6%) and 94.7% (91.3%-98.1%). In combination with a normal ECG, 1) hs-cTnI<LoD had an NPV of 99.6% (98.9%-100%) and sensitivity of 99.4% (98.3%-100%); and 2) hs-cTnI<5 ng/L had an NPV of 99.5% (98.8%-100%) and sensitivity of 98.8% (97.2%-100%). The NPV and sensitivity for the safety outcome were excellent for hs-cTnI<LoD alone or in combination with a normal ECG, and for hs-cTnI<5 ng/L in combination with a normal ECG.

CONCLUSION

Strategies using a single hs-cTnI alone or in combination with a normal ECG allow the immediate identification of patients unlikely to have acute myocardial infarction and who are at very low risk for adverse events at 30 days.

[Acute chest pain]

Patients presenting with acute chest pain are a challenge for attending physicians in private practice and specialists for emergency and acute medicine in hospitals because a wide spectrum of diagnoses may be the cause, ranging from acute myocardial infarction (AMI) to harmless muscular tension. The evaluation of patients with acute chest pain follows basic principles independent of the setting: A thorough clinical investigation by the responsible physician including medical history and physical examination, followed by a 12-channel electrocardiogram (ECG) and further focused diagnostics. The decision about hospital admission, monitoring and further diagnostic steps depends on the estimation of vital risk, the tentative diagnosis and the available diagnostic tools. Besides the ECG, laboratory tests (cardiac troponin, copeptin) and cardiac imaging (primarily the echocardiography) play a key role. Patients who did not necessarily require hospital admission (e. g. after exclusion of AMI) should be offered an inpatient or outpatient concept which enables the timely diagnosis and potential treatment of all relevant diseases in question. The diagnostic strategies need to take into account the pretest probability and for patients with confirmed diagnosis of an acute coronary syndrome (ACS), continuous monitoring and transfer to an emergency department with integrated chest pain unit (CPU) is strongly recommended. In this context, close collaboration between the emergency department and the physicians in private practice should be established.

Biomarker strategies: the diagnostic and management process of patients with suspected AMI

Security standards of our times largely exclude a discharge of patients with chest pain from the emergency departments (EDs) based on clinical assessment alone. Given the increasing use and consequently crowding of EDs worldwide and the large proportion of patients who present to the EDs with, however vague, signs and symptoms of acute coronary syndrome, there is a strong clinical and public health need to achieve a faster but safe rule-in and rule-out of acute myocardial infarction (AMI) to direct patients onto the correct management pathway. A number of approaches for a faster rule-in and rule-out of AMI are currently under research and evaluation and some have already been integrated into current guidelines and/or implemented into the clinical routine in selected centers. This article summarizes these different diagnostic strategies for patients with suspected AMI, using cardiac troponin alone or in combination with copeptin.

Mast cells and acute coronary syndromes: relationship between serum tryptase, clinical outcome and severity of coronary artery disease

Objective

To assess the relationship between serum tryptase and the occurrence of major cardiovascular and cerebrovascular events (MACCE) at 2-year follow-up in patients admitted with acute coronary syndrome (ACS). To compare serum tryptase to other validated prognostic markers (maximum high-sensitivity troponin (hs-Tn), C reactive protein (CRP) levels at admission, Synergy between percutaneous coronary intervention with Taxus and Cardiac Surgery (SYNTAX) score).

Methods

We measured serum tryptase at admission in 140 consecutive patients with ACS and in 50 healthy controls. The patients’ follow-up was maintained for 2 years after discharge. The predictive accuracy of serum tryptase for 2-year MACCE was assessed and compared with hs-Tn, CRP and SYNTAX score.

Results

Serum tryptase levels at admission were significantly higher in patients with ACS compared with the control group (p=0.0351). 2 years after discharge, 28/140 patients (20%) experienced MACCE. Serum tryptase levels, maximum hs-Tn measurements and SYNTAX score were higher in patients who experienced MACCE compared with those without (p<0.0001). Conversely, we found no significant association between MACCE and CRP. The predictive accuracy of serum tryptase for MACCE was set at the cut-off point of 6.7 ng/mL (sensitivity 46%, specificity 84%).

Conclusions

In patients with ACS, serum tryptase measured during index admission is significantly correlated to the development of MACCE up to 2 years, demonstrating a possible long-term prognostic role of this biomarker.

Troponin assay use in the emergency department for management of patients with potential acute coronary syndrome: current use and future directions

Troponins are proteins commonly found in cardiac tissue that are released during myocardial ischemia or necrosis. These troponins can be detected by assays that can then be used to guide clinical decision-making and disposition, especially if the suspected insult is related to acute coronary syndrome. Timing of troponin measurement can be important as elevations may not be detectible immediately after an insult. New assays have been designed to detect troponin con-centrations previously too low to be detected by conventional assays. These tests are known as high-sensitivity cardiac troponin assays. Current research is aimed at evaluating the clinical sig-nificance of troponin elevations detected by these new assays especially in management of pa-tients with suspected acute coronary syndrome. A number of risk-stratification scores exist to assist physicians with evaluating chest pain in the emergency department in the context of de-tection (or absence) of troponins in systemic circulation. Additionally, investigators are working to integrate data generated by hs-cTn measurements into existing and new risk-stratification scores.